Heat-conductivity apparatus



Patented Aug. 14, 1928.

UNITED STATES FRANCIS in. ROWAN, or BESSEMER, ALABAMA.

fHEAT-CONDUCTIVITY APPARATUS.

Application filed January 9, 1926. Serial No. 80,379.

'My invention relates to improvements in apparatus for ascertainingthe conductivities of substances, and it consists in the combinations, constructions and'arrangements herein described and claimed.

An object of the invention is the provision of a simple and reliable apparatus which afl'ords facilities for ascertaining therelative heat conductivity of any substance, whether solid or fluid, theheat conductivity of a given substance, as for example common silver, being taken asastandard.

Other objects and adVanta-geScfthe invention will be apparent from the following description, considered in conjunction with the accompanying drawings, in which Figure 1 is a plan view of a heat conductivity ascertaining apparatus embodying the invention,

Figure 2 is a relatively enlarged vertical section through the apparatus taken substantially along the line 2 20f Fig. 1 and showing in full line a thermometerin one of the test vessels of the apparatus,

Figure 3 is a'vertical sectionthrough a modified form of test vessel and of fragmenary portions ot'associatedparts of the apparatus.

In carrying out the invention I-"make use of an upright tubular gas burnerl which preferably is a conventional Bunsen burner. A flame confining shell includes an inverted frusto-conical body portion 2 and a tubular attaching portion 3 which is located at the smaller end of the body2 and which fits on the upper end portionof the burner 1. The body 2 has a cylindrical portion 4- at its upper and larger end and preferably is made of steel. An inverted conical flame spreader 5, which also preferably is made of steel, is suspended WltlllIlthe lower portion of the body 2 centrally of the latter and. above the open upper end of the burner 1 by'means of four hanger straps 6 which have the lower end portions thereof secured in any suitable known manner to the top wall of the spreader 5 centrally of the latter and are in engagement at their upper ends with the inner wall of the body 2at places spaced regularly around the inner circumference of the latter. If desired, the'hanger'straps 6 may be secured to the body 2 positively, as by means of rivets, not shown or like fastening devices. Thus the flame spreader 5 is in efiect merely a metal. cone riveted to a hanger 6, this hanger consisting of four bent metal strips or legs. It will be seen that the assembled member, while described as being riveted'to the body 2, couldbemerely suspended in it by the contact of the legs withthe bodywall and'by its own'weight.

Four arcuateflame target plates 7 of substantial thickness are arranged in a circular series in the cylindrical portion 4 of the flame confining shell. Each target plate 7 has a socket 8 in its outer wall in alignment with an opening 9 in the cylindrical portion 4 of the flame confining shell. The target plates 7 are supported within the cylindrical portion 4 of the flame confiningshell by the inner end portions of rods 10 which extend through the openings 9 and through heat insulating and spacing rings 11, which preferably are made of asbestos, into the sockets 8 with which they may be engaged in any suitable known manner, as by means of threads, as at 12, if desired. The spreader 5 is so-positioned as to evenly heat the target plates 7.

One of the rods 10 is made of the given material, the heat conductivity of which is taken as a standard. This material preferably is silver. The remaining rods 10 are made of the materials, the heat conductivities of which are to be ascertained, and these remaining rods 10 therefore maybe termed test rods. The respective rods 10 are equal in length and size and the outer end portions of these rods support test vessels which may have the construction indicated generally at 14 in Figures 1 and 2. Each vessel .14; comprises an open inner shell 15 made of brass and having a'relatively thick bottom 16 and an outer casing or covering 17 which is made of asbestos and includes a removable lid,lin-

dicated at 18, *for covering the upper end of l the brass casing 15. The bottom 16 'of the brassinner casing of each vessel 14 has a radial socket 19 for the reception of the outer end portion of the associated rod 10 and'in line with an opening.20 inthe associated heat insulating covering or casing 17. The rods 10 of course extend through the openings 20 into the sockets 19 and the portions of the rods 10 which. extend between the cylindrical portion 4. of the flame confining shell and the vessels 14 are'coveredby sleeves 21. of asbestos. The lids 18 of the insulating coverings of the vessels 14 may have inclined openings 22 and a thermometer, as at 23 in Figure 2, may be inserted through the openings 22 in the insulatinglid of each vessel into the space Within that vessel.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. The vessels 14 are filled with water. The flames from the burner 1 will impinge against the target plates 7 and will heat the respective target plates to the same extent. Heat will be conducted by the rods 10 to the brass inner casings of the vessels 14 according to the conductivity of the respective rods 10. As hereinbefore stated, one of the rods 10 is made of a given material, preferably silver, the conductivity of which is taken as the standard, and the remaining rods 10 are made of the substances, the heat conductivities of which'are to be ascertained. The rise of temperature of the liquid within each vessel 1st will be indicated by the thermometer which depends in that vessel and the increases of temperature in the remaining vessels 14 are compared with the increase of temperature in the vessel 14 that is carried by the standard rod-l0. Relative calories of heat may be calculated, which will give the relative conductivity of the test rods.

The test vessel shown in Figure 3 is especially well adapted for ascertaining the relaative heat conductivity of gases or liquids and plastics or soft solids, such as clay, sand, etc. This modified form of test vessel comprises an open inner brass shell 30 having a relative thick bottom 31 and being covered by an outer casing 32 of asbestos including a body which is of somewhat greater height than the body of the inner shell 30. The

insulating outer casing 32 also includes a lid 33 which rests on the outturned flange 34 of the brass test cup 35. The brass test cup 35 is disposed within the upper part of the brass inner shell of the test vessel in spaced relation to the inner wall of the latter and the flange 34. rests on a spacing and insulating ring 36 of asbestos which fits within the upper end portion of the body of the insulating shell 32 and is superimposed on the upper edge of the body of the brass inner shell 30. The test cup 35 thus is completely insulated from the brass inner shell 30 of the modified form of test vessel. The space Within the. body of the modified form of test vessel will be airtight when the test cup 35 and the lid 33 are in place as shown in Figure 3 by reason of the asbestos lid 33 being tightly fitted and sealed with sealing wax, insulating glue, paraliin or the like after the thermometer is in place and at this time, an opening 37 in the heat insulating lid 33 is in communication with the space within the test cup 35 but out of communication with the space within the test vessel. The opening 37 is adapted to permit a thermometer to be projected therethrough into the space within the test cup. The bottoms 31 of the brass inner shells of the modified form of test vessels are formed with radial sockets 38 for the reception of the outer end portions of the rods 10, such rods of course extending through openings, as at 39, in the heat insulating outer shells of the casings of the modified form of test vessels.

When the-modified form of test vessel is employed, one of such test vessels will replace each of the test vessels l4 and the respective rods 10 may be formed of the same or different substances of known conductivity. The test cups 35 will be filled with water and the gases or liquids, the relative conductivities of which are to be ascertained are placed in the respective test vessels. The increases of temperature within the respective test cups 35 will be indicated by the thermometers which depend in such cups and since the relative conductivities of the respective rods 10 are known, the differences of temperature increase in the respective cups 35 will supply data from which the relative conductivities of the gases or liquids within the bodies of the test vessels can be calculated. The heat conductivity is calculated as follows: Say for instance metal bars are being used as conductors from the inner brass or copper ring to the metal vessel, heating for say one minute (cold distilled water being in the vessels at the beginning and its temperature having been recorded). At the end of the minute the temperature is taken simultaneously in all of the cups. The rise in temperature (centigrade degrees) multiplied by the number of grams of water in the respective vessels will give the number of calories. This should give the relative heat transference of the difi'erent metal bars that are being used as conductors. The vessels holding the same amount of water, the relative calories will give relative heat conductivity.

Obviously, my invention is susceptible of embodiment in forms other than that which is illustrated in theaccompanying drawings and I therefore consider as my own all such modifications and adaptations of the form of the device herein described as fairly fall within the scope of the appended claims.

I claim 1. A test device for ascertaining the heat conductivity of substances, a shell, means for heating the shell. a plurality of radially disposed heat eonducting elements attached to the shell and having different degrees of heat conductivity and all being subjected to and heated uniformly by said heating means, and means associated with the heat conducting elements for indicating the temperature thereof.

2. A relative heat conductivity apparatus comprising a flame confining shell adapted for attachment to an upright burner, a plu rality of similar flame targets within the upper part of said flame confining shell, flame spreading means for directing the fit) flame of the burner against said targets uniformly, rods corresponding in number with said targets and each being in contact at its inner end with a target, test vessels carried by the outer end portions of said rods, each test vessel including an inner metallic casing in contact with the associated rod an d adapted to hold a liquid, and heat insulating mate rial covering the portions of the rods which extend between said flame confining shell and the associated test vessel, one of said rods being made of a material of standard heat conductivity.

3. A relative heat conductivity apparatus comprising a flame confining shell adapted for attachment to an upright burner, a plurality of similar flame targets within the upper part of said flame confining shell, flame spreading means for directing the flame of the burner against said targets uniformly, rods corresponding in number with said targets and each being in contact at its inner end with a target, test vessels carried by the outer end portions of said rods, each test vessel including an inner metallic casing in contact with the associated rod and adapted to hold a liquid, and heat insulating material covering the portions of the rods which extend between said flame confining shell and the associated test vessel, one of said rods being made of amaterial of standard heat conductivity, and heat insulating means spacing said targets from said flame confining shell.

4. A relative heat conductivity apparatus comprising a flame confining shell adapted for attachment to an upright burner, a plurality of similar flame targets within the upper part of said flame confining shell, flame spreading means for directing the flame of the burner against said targets uniformly, rods corresponding in number with said targets and each being in contact at its inner end with a target, test vessels carried by the outer end portions of said rods, each test vessel including an inner metallic casing in contact with the associated rod and adapted to hold a liquid, and heat insulating material covering the portions of the rods which extend between said flame confining shell and the associated test vessel, one of said rods being made of a material of standard heat conductivity, said vessel also including an outer casing of heat insulating material including a lid which constitutes a cover for the metallic inner casing, said lid having an opening 'for the reception of a thermometer.

5. A relative heat conductivity apparatus comprising a flame confining shell made of metal and having a body of inverted frustoconical shape, said body having a tubular extension at its smaller end adapted to fit on the upper end portion of an upright gas burner tube, said body also having a substantially cylindrical extension at its upper and larger end, the cylindrical portion of the flame confining shell having regularly spaced openings, metallic flame targets of arcuate form corresponding in number to the openings in the cylindrical portion of said flame confining shell, each of said targets having a radial socket in its outer Wall, metallic rods extending through the openings in the cylindrical portion of the flame confining shell and fitting in said sockets of the target for supporting said target in the upper part of the flame confining shell, heat insulating rings on said rods between said targets and the adjacent portions of the flame confining shell, a flame spreader, regularly spaced hanger members supporting said flame spreader within the body of the flame confining shell centrally of the latter for deflecting flames from the burner against said targets uniformly, said hanger members also deflecting the flames from said insulating rings, means carried at the outer ends of said rods for indicating temperature changes, heat insulating means covering the portions of the rods which extend between said temperature indicating means and the cylindrical portion of said flame confining shell.

6. In a device of the character described, a test vessel comprising an inner metallic casing open at its top, an outer heat in sulating casing fitting on the metallic inner casing and including a removable lid, said metallic inner casing having a radial socket in its bottom and said insulating outer casing having an opening in line with said socket for the reception of a heat conducting rod for engaging with said socket, said lid of the insulating outer casing having an opening through which a thermometer may be projected.

7; In a device of the character described, a test vessel comprising an inner metallic casing open at its top, an outer heat insulating casing fitting on the metallic inner casing and including a removable lid, said metallic inner casing having a radial socket in its bottom and said insulating outer casing having an opening in line with said socket for the reception of a heat conducting rod for engaging with said socket, said lid of the insulating outer casing having an opening through which a thermometer may be projected, a cup of heat conducting material having a flange at its upper end fitting in the body of the insulating outer casing above the body 01". the metallic inner casing, and a heat insulating ring spacing said flange from the upper end of the body of the metallic inner casing, the space within said cup, being disposed underneath the opening in the lid of the heat insulating outer casing.

FRANCIS M. ROWAN.

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